The present invention relates to the field of snowplows, specifically, to the use of visors or foils which would reduce and control the blowing of snow up over the upper edge of the moldboard of the plow. Such snow may strike the windshield of the plow, the body of the plow vehicle, and strike or enter into the engine of the plow vehicle. This causes obstruction of the view of the driver of the vehicle, damage to the body of the plow vehicle and impairment of the vehicle's engine performance.
In a normal snowplow, without a snow deflector system, snow may come up over the top of the snowplow and ultimately cause a vision problem for the driver both from the snow blown in the path of his vision and the snow impacting on the windshield. Also, the snow can be drawn into the engine causing impairment of engine performance or even damage to the engine itself. Further, in areas where sand and/or salt is put on the road to help increase traction and melt ice and snow, the sand or salt has a tendency to mix with the snow, salt, and sand can cause a sandblasting effect upon the body of the vehicle thereby significantly reducing the life of the body of the vehicle by removing the paint from the vehicle and exposing the bare metal surface of the vehicle to direct contact with the snow and road salt.
There have been many attempts to solve this problem but none resolve it as simply and effectively as the design of the instant invention.
For example U.S. Pat. No. 2,385,996 (Phillips) discloses a snow flow deflector. However, unlike the instant invention Phillips shows the leading edge of its deflector to be at or below the upper edge of the moldboard. This is completely contrary to the structure of the instant invention. Further, the design of Phillips allows its deflector to tip back, as a safety feature, when large drifts are encountered. This eliminates the effectiveness of the Phillips device in those situations. Also, the angle iron 5 disclosed in FIGS. 1-3 and structures 40, 1, and 41 of the alternative design disclosed in FIG. 6 of Phillips, all create choke points which will impede the flow of snow under the deflector causing a blockage which would render the deflector inoperative. Additionally, Phillips discloses no belt or barrier structure for partially containing the flow of snow particles as they are pushed out in front of the moldboard. The final alternative structure disclosed in FIG. 7 of Phillips is completely different in structure from the instant invention. U.S. Pat. No. 3,432,947 (Peitl), is also structurally and conceptually different from the instant invention. Peitl does not disclose the use of the belt barrier that is hung from the top edge of the moldboard in the instant invention. Further, the concept of the instant invention is to provide a foil which provides minimum resistance to the flow of snow and air that passes through and over it. The steep angle of orientation taught in Peitl (" . . . said deflector having top and bottom edges, a forward surface and a back surface"; claim 1, U.S. Pat. No. 3,432,947 (Peitl)) provides greater resistance to air flow than the instant invention having leading and trailing edges and top and bottom surfaces and therefore is counter to the design of the instant invention. The design of the Peitl deflector is such that it does not in truth direct any air or snow into the space between his deflector B and the back side of the blade A because the air and snow mixture, upon leaving contact with the upper edge 31 of the blade continues forward in the direction that the vehicle is moving past the opening through which Peitl intends the snow to go through. There is so much dense snow moving in an upward direction that no air or snow can possibly change direction to get into the space that Peitl wishes it to go. The faster the vehicle moves forward the higher into the air the snow is thrown. This renders the deflector of Peitl useless. Peitl located his deflector (referred to as number 30 in his FIGS. 1 & 2) behind the flow of air/snow coming over the moldboard. Peitl's FIG. 2, depicts the flow of air/snow in relationship to a standard moldboard being operated at a very low speed. This is apparent because the snow is not flowing over the top of the moldboard. When operating at normal speeds, the air is compressed in front of the moldboard, it can escape only out the delivery end of the plow or over the top of the moldboard. The design of the standard moldboard picks up the snow and hurls it upward and slightly toward the delivery end of the plow. At the point the snow/air loses contact with the top of the moldboard it is traveling in the direction dictated by the shape of the moldboard, much the same as a bullet is aimed by the barrel of a gun. In this case, it will continue traveling on a tangent to the arc of the moldboard; its velocity will be that of the plowing vehicle. Therefore, in FIG. 2 of Peitl's patent, it is easy to see the air/snow will pass in front of and over his deflector when traveling at normal operating speeds disproving the arrows in his FIG. 2. The intake of the Peitl system as depicted in his FIG. 2, shows a large opening between the top of the moldboard and the leading edge of the deflector. However, the outlet of the system has a very small opening between the trailing edge of the deflector and the moldboard. This makes the passage of air and snow through the Peitl system, in the volumes required to be effective, impossible. His system of a venturi is completely contrary to the design of the present invention. The leading edge of the foil of the present invention is normally placed in a position eight (8) to twelve (12) inches above the top margin of the moldboard with the front edge and back edge being located in the same plane. The air just in front of the moldboard is highly compressed by the forward movement of the plow vehicle. This pressure is equalized by air escaping out the delivery end of the moldboard and over its top margin. This results in air traveling in a near vertical direction at a very high velocity from ground level up and passing just in front of the belt. The concave shape of the foil placed above this vertically traveling air gently re-directs it over and down behind the moldboard, without impeding its flow, unlike teachings in prior art. The top surface of the foil works similar to the top surface of an airplane wing. In an airplane wing the distance over the entire top of the foil from the front edge to the back edge is longer than the distance, in the same plane, from the front edge to the back edge on the under side. This faster moving top air joins at the back edge of the foil with the air already moving in a downwardly direction to help force all the air at the back edge of the foil in a downwardly direction behind the moldboard. The snow particles from in front and in back of the moldboard are caught in this air flow and are forced down to the ground directly behind the moldboard and under the vehicle. Patent DE 3736-707-A (Beil) depicts a device which is ridged in design, mounted on the top of a moldboard which has very small pressure relief ports between the device and the moldboard. For the most part this device equates to what is normally referred to as a belt in the United States. The ports are so small they restrict the air flow but allow air/snow to escape without the velocity or guidance to direct it down and under the plow vehicle. Other references include U.S. Pat. No. 1,900,703 (Frink), U.S. Pat. No. 1,926,071 (Soule), U.S. Pat. No. 2,904,904 (Krueger), and U.S. Pat. No. 4,459,769 (Willis). None of these references disclose either the use of the barrier belt or the use of a snow deflector which allows the flow of air and snow rising over the top edge of the moldboard to be deflected behind the back side of the moldboard and underneath the snowplow vehicle.
The main objective of the instant invention is to capture and control snow that rises over the top edge of the moldboard of the snowplow.
It is an advantage of the instant invention to allow plowing at high speed, this leaves the road in better, cleaner condition. It is a further advantage of the instant invention that the airflow directed behind the moldboard and under the vehicle prevents any snow or other particulate matter that may pass under the moldboard from being blown toward the vehicle. This is because the airflow from the foil at the top of the moldboard blows the particles coming from under the plow, down and away from the body of the vehicle and the engine of the vehicle.